Post-surgical complications are most common in older adults. While a number of factors contribute, one key determinant is malnourishment. Malnutrition ? particularly low protein intake ? is seen in up to 86% of older adults at hospital admission; however, the prevalence of malnutrition in older Veterans is unknown. Malnutrition and post-surgical complications are linked through two critical observations: 1) malnutrition dramatically reduces the ability of older adults to overcome postsurgical health stressors, and 2) nutritional status is likely to deteriorate further during hospitalization and after discharge. Despite convincing evidence that perioperative nutrition interventions can improve surgical outcomes, such interventions have not been developed and implemented for our Veterans. Thus, there is a critical need to initiate the required steps to identify and reduce malnutrition in older Veterans who are anticipating surgery. The overall objectives of the proposed research are: 1) to validate screening and assessment tools to quickly and accurately identify perioperative malnutrition in Veterans, and 2) to pilot test a ?perihabilitation? intervention of protein enhanced supplementation to identify its feasibility, fidelity, and acceptability, and 3) to determine the effect size of physical function in preparation for a larger clinical trial. The Perioperative Optimization of Senior Health Program (VAPOSH), a new interdisciplinary program at the Durham VAMC, offers a unique opportunity to develop and pilot test approaches for addressing perioperative malnutrition. Demonstration of the functional impact of perioperative protein supplementation for malnourished older Veterans will support this research proposal seeking to identify and treat perioperative malnutrition and improve postoperative outcomes in older Veterans. The Aims of this project are: 1) to select the appropriate nutrition screening and assessment tools for VAPOSH Veterans and employ them to characterize malnutrition prevalence and severity and establish cut-off values associated with malnutrition, 2) to conduct a pilot randomized controlled 6-week trial of enhanced protein supplementation in a population of malnourished Veterans undergoing elective surgery; 2.1) use a pilot trial to evaluate the feasibility, fidelity, and acceptability of a perioperative protein- enhanced intervention compared to an educational control; and 2.2) to determine the effect size for planned future studies of enhanced protein supplementation in malnourished Veterans, with physical function as the primary outcome of interest. Aim1 encompasses an observational, prospective study that screens and evaluates 75 VAPOSH patients undergoing elective surgery 1) to report the prevalence of being malnourished or at risk of being malnourished in VAPOSH patients, 2) determine the criterion validity of the Nutrition Risk Screener-2002 and Patient Generated-Subjective Global Assessment tools, and 3) identify cut-off value associated with malnutrition. Aims 2.1 and 2.2 will pilot test a ?perihabilitation? intervention in malnourished older Veterans undergoing elective surgery to assess 1) the feasibility, fidelity and acceptability of a higher protein supplement before and after surgery and 2) the effects of a higher protein supplement on the primary outcome measure, physical function and secondary outcomes of interest. Malnourished VAPOSH Veterans will be randomly assigned to either an education (nutritional counseling) control arm or high-protein perihabilitation arm. Participants in the high-protein arm will be provided with high quality protein supplements that will bring their protein intakes to at least 30 grams for each of the 3 meals per day. The successful completion of these aims will provide important findings that will support the development of novel and much needed approaches to intervene for malnutrition in Veterans before, during and after surgery.